This invention relates to a method and apparatus for tab bussing of multicell batteries. More specifically this application relates to a tab bussing structure using a holding device for fastening the tabs and a method for fastening the tabs.
In the prior art a thermally induced bond between the tabs of the single cell batteries was utilized to build the multicell batteries comprising a number of single cell batteries. See U.S. Pat. No. 4,152,825 Bruneau; U.S. Pat. No. 4,070,528 Bergum; U.S. Pat. No. 4,091,184 Erisman; U.S. Pat. No. 3,907,599 Fanciullo.
However, to make a thermally induced bond it is necessary to apply high temperature and high pressure, which makes the manufacturing process of such batteries burdensome. It can also damage the battery internal components. Therefore, the thermally bonded tab bussing structure may not be preferable for some batteries.
The first objective of the proposed invention relates to a manufacturing process of making the multicell battery without use of high heat or high pressure.
The second objective of the current invention relates to an energy efficient multicell battery. It is very important for purposes of creating an energy efficient electrical car to have a small and energy efficient multicell battery. Indeed, the main problem facing the creation of a commercially viable electrical car is the necessity to place inside the very limited car space sufficient amount of energy producing capabilities. The smaller and the more energy efficient the battery, the more energy producing capabilities can be placed inside the limited car space. Therefore, a small and energy efficient battery can make the real difference in the race for the commercially successful electrical car.
Regular cars with gasoline engines also benefit from energy efficient SLI (starting, lighting, igniting) batteries. A good SLI battery is designed to deliver a relatively high impulse of electrical power. Therefore it is also desirable to provide sufficient electrical power per cell which can be delivered by a small energy efficient multicell battery.
High internal electrical resistance prevents a multicell battery from delivering the maximum electrical power per cell, because significant amount of electrical energy is dissipated inside the multicell battery. Therefore, it is paramount for a multicell battery to have small effective electrical resistance.
The effective electrical resistance of the multicell battery depends on many factors. One of those factors is the presence of gaps between the tabs of the tab structure. The electrical resistance of the multicell battery is increased by these gaps in the tab structure. The thermally induced bonded batteries, described above, have relatively high resistance, because their tab bussing structures have significant gaps therein between tabs.
A second objective of the present invention is to offer a new fastener method of tab bussing of the multicell battery because this method permits one to build a multicell battery which has low electrical resistance and occupies a very limited space.